Nature of the beasts: More to it than cats

Last updated 05:00 25/01/2013

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OPINION:
It's the nature of nature that when man upsets it, there is no going back. True, there are exceptions, and the ecological islands developed in various parts of New Zealand illustrate that. But they are like critically ill patients on life support - reliant on others for their continued existence.

Man has historically played with the balance of nature, wittingly or unwittingly. New Zealand's flora and fauna has suffered immensely, in many cases fatally, as a consequence. This land was once ruled by giants, flightless birds and long-living, slow breeding species. With the exception of three species of bat, there were no mammals.

When the balance has been tipped at the expense of native wildlife it has usually been out of sheer ignorance. How could Maori settlers have known their hunting of a food source, moa, would lead to its extinction - and consequently the demise of the Haast eagle, the biggest raptor we never saw?

European influence on the ecological balance was co-ordinated and destructive. Where Polynesian settlers brought the dog and rat, the Europeans introduced species for meat, commerce and familiarity - deer, goats, pigs, rabbits, hares, possums and garden and game birds.

Mice and new species of rats arrived as stowaways. Cats and fish and caged birds arrived as pets and soon colonised the wilds. Those animals and many more came, saw and conquered.

When the damage was recognised it was too late, and the answer, as in other countries, was to fight one pest by introducing another. When New Zealand's rabbit population boomed, it was decided to ignore warnings and introduce stoats. Now we also have weasels and ferrets. New Zealand is not alone in suffering the consequences. Australia's introduction of the cane toad was a classic act of folly.

This week Gareth Morgan, variously an economist, commentator, philanthropist and wannabe football expert, has put up his own plan for redressing the balance. He declared war on the cat, arguing it should be wiped out in the wild and not replaced in the home. His Cats to Go campaign makes some pertinent points, but it highlights the difficulty in repairing a damaged environment.

Like previous attempts, it could also backfire. Removing cats will create a more friendly urban environment for rats and mice. Evidence already points to the rat causing more damage than the cat.

Cats are a threat to native wildlife, but so are dogs. One roaming canine was blamed for killing 500 kiwi over a six-week period in the Waitangi State Forest in 1987. Most guests, though, at the nightly feast on natives in the bush are rodents, mustelids and about 30 million marsupials - the bushtail possum.